Receivers with LFE 80Hz-Crossover, are Front Spkr sets missing their acoustic-mark (1 Viewer)

[Paul A. Robinso]

As we(HT-audio enthusiast)sit in our hometheater
"sweet-spot" what are we not hearing.....
Most receivers offer LFE-Crossover at 80 or 100Hz
While for an example your front(Left/Right/Center) set of speakers are designed with a LFE-crossover at 150Hz.
For lack of a more technical term, this dead sonic space
between 80Hz and 150Hz is unused (by the speaker and my ear)and this scenerio could just as well apply to the surround speaker's LFE-crossover.
Am I being to pickey or what your opinion.
Oh, is their a technical/audio term for this scenerio.

 

[Jack Gilvey]

There are some speakers sets that applies to, I would consider them lacking. You certainly want speakers that can give good response down to their intended crossover.

Are you referring to a specific set?

 

[BruceD]

If I were picking speakers (especially mains) for an 80Hz crossover, I would want them to have a -3dB response point down to 40Hz.

This means reasonable response one octave lower than the crossover. This typically allows the smoothest blend between sub and main speakers.

Now, all of this also depends on what slope (shallow or steep) the HT processors xover uses as well as the natural low frequency rolloff (slope) of the main speakers. For example, ported speakers will have a different slope than sealed speakers.

It turns out to be a pretty complicated exercise to get right, but it helps to understand all the variables.

BruceD

 

[Chris PC]

I agree that receiver crossovers should go to at least 60 hz, but most are only 80 or 100hz. My front speakers go to 32hz -3 dB, so i could easily get away with 60 hz crossover. My center goes -3 dB to 40 hz, so perhaps my center would be fine at 80 hz.

 

[Jimmy P]

Yes,dont buy speakers with a lower limit of 150Hz and a receiver with a 80Hz sub crossover.

I know what you are saying,and people should pay attention

to the various hardware combinations they are putting together to avoid problems like you have described,and then

wonder why their system sounds like crap.

 

[Jeremy Anderson]

For lack of a more technical term, this dead sonic space between 80Hz and 150Hz is unused (by the speaker and my ear)and this scenerio could just as well apply to the surround speaker's LFE-crossover.

I think I understand what you're trying to say now. If your receiver uses an 80Hz crossover, BruceD is correct in saying that you should select speakers that can hit a -3dB point somewhere in the 40-50Hz range. That's why I always warn people away from JBL's NSP-1 package or any other speakers that roll off at 80Hz. Too many people think speakers with an 80Hz rolloff point match up to a receiver with an 80Hz crossover, and that's not true (since it will leave a nice gap from 40-80Hz).

 

[Jack Gilvey]

That's why I always warn people away from JBL's NSP-1 package or any other speakers that roll off at 80Hz. Too many people think speakers with an 80Hz rolloff point match up to a receiver with an 80Hz crossover, and that's not true (since it will leave a nice gap from 40-80Hz).

Actually, the reason I think that the NSP-1 is the best such small package is the lack of such a gap. I have that package used with an Onkyo 575x, and they get down to the crossover rather well, certainly no 40-80Hz gap. Now, larger speakers will certainly be able to play louder at the crossover, no doubt.

Energy Take 5...now there's a gap, sats are much too small.

 

[Pete Mazz]

If the speakers roll off near 80 Hz, they should be ideal for HT using a standard 12 dB 80 Hz HP filter. The sub gets rolled off at 24 Db, so the natural roll off of the speaker combined with the 12 dB roll off of the xover should balance out thru the xover region nicely.

Pete

 

[Jeremy Anderson]

For the sake of argument, you have a THX-spec 80hz crossover with 12dB/octave high pass, and each speaker naturally rolls off at about 12dB/octave past its -3db point (I understand that this is dependant on the speaker, but this is just for the sake of argument). Here are the two scenarios:

1) A speaker whose -3db point is at 40Hz.

80Hz = neutral

40Hz = -15dB

2) A speaker whose -3dB point is at 80Hz.

80Hz = -3dB

40Hz = -27dB

While I understand that this is an oversimplification, this is just an example. I don't want to go pissing off fans of the JBL's or anything, but they just won't transition as well as a speaker with a slightly better rating. I'll give you this though -- they're great for a beginner package.

I think I've caused enough arguments for today... so I'm going to bow out for the night.

 

[Jack Gilvey]

I don't see why anyone would get pissed off. I'm just giving my experience as an owner/user, specs aside. And if being -3db at the crossover is the worst deviation in response someone has, then they have astounding in-room performance (a rather unlikely situation).
Yes, they are a great "beginner package". Or, for someone like me, who needs something 'til he builds his own. I'll take it over a few of the more costly sets I've heard, though.

 

[Pete Mazz]

For the sake of argument, you have a THX-spec 80hz crossover with 12dB/octave high pass, and each speaker naturally rolls off at about 12dB/octave past its -3db point (I understand that this is dependant on the speaker, but this is just for the sake of argument).

Exactly!

Then a speaker with an F3 of 80 Hz would perfectly blend with the normal 24 dB/octave LP filter that most HT processors use for bass management

Pete

 

[BruceD]

Speaker building specs say a -12db rolloff only occurs with acoustic suspension (sealed) speakers.

This means most of the speakers we are discussing here are ported and don't have a natural -12dB rolloff. They don't really match up well with the receivers -12dB high pass, instead they cause problems in the crossover region (not a smooth integration between sub and mains).

I own AR-3a (Acoustic suspension) speakers (don't use them now), Dynaudio Contours (with passive radiators) I do use them in my HT/2-channel system, and demoed a small variety of bass reflex (ported speakers) including B&W with my system.

The -3dB point and low end rolloff is different on all of them. A symmetrical -24dB high and low pass (Linkwitz-Riley) crossover worked better on all of these speakers than anything provided by a Yamaha receiver or Technics pre-pro.

That's what I use now with my Dynaudios, a Marchand electronic crossover, crossed over at 60Hz with a Parasound 5 channel amp.

BruceD

 

[John Morris]

And if being -3db at the crossover is the worst deviation in response someone has, then they have astounding in-room performance

Jack: You rock!(got that from my 7 year old son... I think it must be the ultimate compliment )Anyway, I am wondering if those folks who are worried about a 3db deviation at 80Hz have ever run a SpectraPlus analysis of their theater? I can only wish that my system/room spec'd out at +or-3db from 20 to 20!

 

[Bryan Acevedo]

Jeremy, I think there is one flaw in your argument.

1) A speaker whose -3db point is at 40Hz.

80Hz = neutral

40Hz = -15dB

2) A speaker whose -3dB point is at 80Hz.

80Hz = -3dB

40Hz = -27dB

You are implying that the speaker is attenuating the signal another 12 db. That isn't true. What that -3db point means is that a FULL level signal will be 3 db quieter and that is the maximum the speaker can produce at that frequency relative to the rest of the range.

If you give it a signal that is 3db lower than the rest at that frequency, then the speaker will be able to produce that signal fully, without any attenuation.

So if a speaker's rolloff and the crossover rolloff are the same, they don't combine to create even more of a rolloff. Two crossovers inline do that, but the speaker isn't acting like a crossover. So in essence, a speaker that starts rolling off naturally at 80 Hz 12 db per octave is totally compatible with an 80 Hz crossover with the same slope. Even a speaker that is totally flat to 20 Hz, is only going to see a level at 40 Hz that is -12 db. A speaker that has -12db response at 40 Hz will produce that signal identically. Now if you give both of those speakers a full level at 40Hz (no crossover), then the full range one will produce a louder signal.

In other words, if speaker A is capable of producing 70db at 40 Hz (-12 db for arguments sake) and speaker B is capable of producing 82db at 40 Hz, if you feed both of them a -12 db signal (70 db absolute level) at 40 Hz - they will be producing at the same level. Speaker A isn't suddenly going to drop it another 12db to 58db. That's just not how it works.

The only time its rolloff comes into play is if you try to give it a signal that is louder and lower than it is able to play. In the example above, if you tried to give both a full signal (82db) at 40 Hz, then speaker B would be able to produce that level, while speaker A would probably begin to distort depending on its design.

Just had to point that out.

Bryan

 

[Howard_S]

Is 80hz the ideal crossover or something? Is generally higher the better or lower the better assuming you have the most capable speakers etc.

 

[Bryan Acevedo]

80 Hz has basically been tested as being the optimal setting for not being localizeable. Most people agree that anything lower than this is not directional. However, there are people that say they can tell what direction lower frequencies are coming from.

This goes back way before the Home Theater days. I remember about 10 years ago, a guy I worked with was a speaker designer, and he told me the best crossover point for a sub was 80 Hz. We were talking about car audio subs, so this is not just something the Home Theater folks came up with.

Bryan

 

[Bryan Acevedo]

No one else has anything to add/rebut/say about my post?

Bryan

 

[Paul A. Robinso]

:star: :star: :star: I agree with most of you and can we all agree that this very topic all Receiver's Bass Management (Wheather THX/DTS requirements) crossover for the Front and Surround speakers should be a marriage/key
with the speaker's "Low Frequency Response".
Guys this is what I meant..... :frowning:
Jeremy, LFE covers(up to 200Hz)100th of 20,000Khz.
Ohh, Jeremy thanks, setting my Sub at a higher than 80hz
crossover, to 120Hz gave me abrouder/deeper bass.
A 1000.00$ vs a 2000.00$ or greater$, speaker set.
The mix or overlay of your Front or Surround
Speaker's Low Frequency Speaker's Limit with what most mid-level receivers/amps (be it 80hz/100hz/120hz) Small/Large crossover is where the the Hometheater sound we
want to achieve begin and ends.........
Also I agreed, it's only reasonable to think
a speaker's Frequency limit varies -/+2db to -/+3db
for a smoother "Surround Sound", through in Timber matching, Delay, A/V-Sync etc: and well you know....
Now if I can interest someone in buying a set of 2-year
old set of Polk-RM5400-series (Hey I didn't know then
what I know now) Yes the Center down to 125Hz
the Fronts down to 150hz and
some good news is the 4-Surrounds down to 70Hz
and the Sub....down to 30hz to 200hz
My System Onkyo receiver, TXDS898, it's great.
Toshiba HD-Monitor, 40H81. Awaiting....
Onkyo Prog/DVD-A/THX-Ultra DVD-Player DV-S757.

 

[Phil Iturralde]

Jack Gilvey, myself and other JBL NSP1's users have discovered what Brent Butterworth meant when he documented in his ETown JBL N24 speaker review (part of the JBL NSP1 package)
Quote:



. . . -- unlike the SuperZero XU or the ProMonitor 80, this speaker is very easy to match up with practically any subwoofer.




Jack uses the Sony sub, . . . I use the Audio Source sub, but in both cases, the blending between our 'subs' and NSP1 is excellent. (I MAX'd out the AudioSource Crossover and let my Yamaha 90Hz X-Over do it's job!)

When Tom Nousaine performed his standard speaker bench-marks on the JBL NSP1 (Sound & Vision, Jan. 2001 issue), the frequency chart reveals why Brent Butterworth wrote what he wrote!


Frequency Response
N-24 front left/right... 89 Hz to 18.9 kHz ±2.7 dB
The left/right front speakers were averaged over a ±30° window, with double weight given to the most common listening angle, 30°.

N-Center................ 89 Hz to 20 kHz ±5.5 dB
The center speaker's response was averaged over ±45°, with double weight directly on-axis,

N-24 surround........... 89 Hz to 18.4 kHz ±3.2 dB
Sound delivered to the listener's ears from surround speakers will be reflected from room surfaces, so their response was averaged over a ±60° window with double weight given to the widest off-axis angles.

Tom Nousaine noted in the LAB Report: "JBL's N24 left / right satellite had smooth, uniform response over the entire ±60° window."

The above chart also reveals why these following reviewers wrote about the NSP1's, . . .

Amazon.com Editorial Review by Wayne Garcia NSP1 Speaker Package

(partial quotes) As for the NSP1 system's sound, starting with music only, the first thing you'll notice is that it produces surprisingly full audio. Jazz CDs sound rich and clear, . . . Trumpets and saxophones come through with terrific, brassy texture and bite, . . . Vocals are uniformly good--articulate, focused, and well balanced. With orchestral music, the N24s throw a relatively wide soundstage, with more than a hint of depth (that is, of the sonic space extending beyond the speakers).

With DVD-videos, vocal clarity is enhanced by the N-Center, which does a great job of routing the dialogue to the screen. Considering its small size, the complete NSP1 system exhibits very good dynamics, and JBL's close attention to driver matching yields a seamless transition from speaker to speaker, creating a wonderfully complete sonic environment. (end of quote)

====

August 3, 2000 Brent Butterworth for etown JBL NSP1 speaker system

(partial quotes) Look & Feel: This system certainly ranks a notch above most of what's available at this price.

Performance: I've already made detailed performance comments in my reviews of the N24 and N-Center. All I'll say here is that these speakers work together perfectly as an ensemble. The timbre matching is as good as any I've heard; that is, outside of systems that consist of five identical speakers.

The N-Center matches the sound of the N24 extremely well, better than Home Theater Direct's Level Three center matches the sound of its Level Three bookshelf. That excellent timbre matching lends coherence to the sound of the entire system, making movies seem more like I was hearing them in a real theater, not a home theater. As such, I highly recommend the NSP1 home cinema package to anyone looking to get into home theater without emptying his or her bank account in the process. (end of quotes)

Compare the JBL NSP1's Frequency Response with other Sound & Vision equivalent and more expensive speaker frequency charts @ my website, Are Bose Speakers Over Priced vs. Performance??

Watching the dynamic "Pearl Harbor" / SE DVD @ 6 dB below REF Level confirms all the accolades above and then some!!

Next, on the agenda is "Jurassic Park III" & "Rush Hour 2"

For more JBL NSP1 INFO and reviews w/links, see my website Why you should add JBL N & S Series to your audition list!

NOTE: If too many people peruse my website, GeoCities will shut it down for an hour or so (being a freebie hosting & all), . . . so, just bookmark it and view it at a later time!

Just an FYI,
Phil

 

[Holadem]

If you give it a signal that is 3db lower than the rest at that frequency, then the speaker will be able to produce that signal fully, without any attenuation.

OK lets see if I got this: Do you mean if you were to graph the response:
A) you would see the same relative attenuation(-3dB) @ 40Hz compared to the frequencies above at all volumes (which is how I always understood it)
OR
B) The lower the volume the flatter the response (which implies a "limit" at 40Hz that the higher frequencies will surpass by 3dB)
I have always understood it as A). If you send a 100Hz tone and get 90dB, you should get 87dB with a 40Hz tone of the same amplitude.
Am I terribly wrong?
--
Holadem